To most people who watched the widely distributed video of Michael Adebolajo standing in a London street on May 22 talking into the camera of a passer-by while holding a meat cleaver that he had allegedly just used to help kill a British soldier, the young man is, at best, a suspected murderer. At worst, he’s a terrorist. In the eyes of Omar Bakri, Adebolajo is “a freedom fighter.”

“From an Islamic perspective, he is fighting back against the soldiers who are committing crimes against Iraq,” Bakri told TIME in a telephone interview from Lebanon on May 29. Bakri is the founder of an Islamist group named al-Muhajiroun. He and another former leader of the group, Anjem Choudary, say Adebolajo attended meetings of al-Muhajiroun. Adebolajo was “shy and quiet” when he attended al-Muhajiroun rallies in 2003 and 2004, Bakri said.

Al-Muhajiroun is now illegal in the U.K., but experts say that in spite of being outlawed and even without its hard-line founder to guide it in person (Bakri has not been in the U.K. since 2005), the group’s members continue to meet and espouse an extremist vision of Islam that celebrates terrorist attacks. The horrific murder of 25-year-old Drummer Lee Rigby and the revelation soon after that Adebolajo had links to al-Muhajiroun reignited concerns in Britain about the role that extremist groups play in radicalizing young British Muslims. Many Muslim groups across Britain have been quick to denounce the crime, as well as the ideals that al-Muhajiroun and Adebolajo have supported.

Adebolajo quickly became the public face of the attack after the footage from the scene showed him apparently discussing the murder with the passer-by who held the camera. “We swear to you, by the almighty Allah, we will never stop fighting you until you leave us alone,” he tells the camera, his hands apparently soaked with blood. Adebolajo, 28, along with his alleged accomplice, 22-year-old Michael Adebowale, was later shot by armed police at the scene and taken to the hospital under armed surveillance. Adebowale has since been released from the hospital and charged with murder and the possession of an illegal firearm.

Bakri founded al-Muhajiroun in 1983 in Saudi Arabia. The group was later banned from the country and Bakri relocated to Britain. He relaunched al-Muhajiroun in 1996 with the help of Choudary, a British then-solicitor. The group gained notoriety in 2003 when it staged rallies celebrating the 9/11 hijackers, calling them the Magnificent 19, before disbanding in 2004, apparently in anticipation of being outlawed by the British government. But the group is thought to have continued operating under various different names. Bakri left the U.K. for Lebanon in 2005. He was subsequently barred from returning by British authorities. When al-Muhajiroun re-established itself publicly in 2009 under Choudary’s leadership, British authorities officially banned it and its successors.

Throughout its existence, al-Muhajiroun’s leaders insisted it was a nonviolent organization. Even while declaring support for Adebolajo, Bakri insists that although the young suspect “did once upon a time participate in our public activities, we don’t teach people to remove other people’s heads.”

Doug Weeks, a University of St. Andrews expert in radical groups, describes al-Muhajiroun as an extremist organization but says the group does not explicitly incite violence. “I think it’s important to note that this is an ideological movement,” Weeks says. “It’s basically a religious social movement. It’s very porous. People kind of come in and hang out for a bit and then pop out the other side.”

But Usama Hasan, a senior researcher at Quilliam Foundation, a counter-extremism think tank, says Islamist extremist groups like al-Muhajiroun can plant seeds of violence without explicitly inciting it: “Even though they’re not violent, a lot of their ideas cause division and hatred in society in terms of discrimination and the idea that Muslims are superior.”

The murder in Woolwich, however, isn’t the first act of violence committed by people connected to the group. According to a study published in 2011 by the Henry Jackson Society, a conservative think tank based in London, 24 out of 134 terrorists convicted in the U.K. from 1998 to 2010 — or nearly 1 in 5 — were either members of al-Muhajiroun or had known links to the group. Hannah Stuart, a research fellow at the Henry Jackson Society and a co-author of the study, told TIME that since the study was published, “it looks as though that sort of 1-in-5 estimate has roughly continued.” Last month, three British men were convicted of engaging in conduct in preparation of acts of terrorism; one of those men was Richard Dart, a convert to Islam who was shown on camera studying under al-Muhajiroun’s former leader Choudary in a 2011 BBC documentary, My Brother the Islamist.

In 2005, the Labour Party government of Tony Blair established an antiradicalization campaign named “Prevent”; the program was designed to improve relations between authorities and Muslim community leaders. Funding to the program was cut in 2011 under the coalition government of Conservative Party leader David Cameron — a move that has since drawn sharp criticism. Days after Rigby’s death, Hazel Blears, a Labour MP and member of Britain’s parliamentary Intelligence and Security Committee, told the Guardian: “Counter-extremism isn’t just about tackling the people you already know are radicalized. It is about trying to work with local communities before they get to that point so that good decent people in the community can protect young people from being groomed and getting these ideas in the first place.”

And wholesale banning of extremist groups like al-Muhajiroun hasn’t appeared to stop them from operating either. “These guys have been around for a long, long time at this point and are quite resilient,” says Weeks. “So one of the issues becomes, if proscription is intended to prevent them from assembling and doing what they do, the evidence would suggest that it’s not really an effective mechanism.”

Bakri’s comments about Adebolajo and the killing of Rigby are anathema to the majority of Muslims in Britain. Bakri insists his “sect has nothing to do with the majority of those [Muslims] speaking out” and says, somewhat vaguely, he will do what he can to help Adebolajo. More forcefully, he warns against any retaliation on his “brothers in the U.K.” saying, “Believe me, it’s going to make the people wake up and there’s going to be devastation for everybody.”